JPH089105A - Reader for image forming device - Google Patents

Abstract

PURPOSE:To obtain a sharp image by almost uniformizing luminous quantity at a CCD image forming plane from its middle part up to its edge so as to improve the reliability of the image. CONSTITUTION:The reader for the image forming device is a device that is integrated with a light from a light source unit 41 integrated with the light source unit 41, reflection mirrors 43a 43d, a lens 44 and a CCD 1 and forms an image of a light from the light source unit 44 is formed on the CCD 1 through the lens 44. The lens 44 is movably arranged in the optical path so that the luminous quantity on the image forming plane of the CCD 1 is uniformized from the middle part to the ends. Preferably, a projection 44a to shut the optical path is integrally formed to a main body of the lens 44. Or a torus member 44c is provided to the main body of the lens 44 freely turnably and the projection 44a is formed integrally with the torus member 44c.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is used in the field of image forming apparatuses such as copiers and image scanners, in which a light source unit, a mirror, a lens, and a CCD are integrated to read image data of a document or the like. The present invention relates to a reading device (scanner unit) that includes a light source unit and forms an image on a CCD.

[0002]

2. Description of the Related Art Light source unit, mirror, lens, CCD
In a reading device integrally provided with a housing, when the reflected light emitted from the light source unit and reflected by an original or the like forms an image on the CCD surface through a mirror and a lens, the light in the lamp tube axis direction Due to the variation of the light quantity and the aberration of the light due to the light passing through the lens, the phenomenon that the light quantity in the central portion of the CCD image forming surface is larger than that in the end portion occurs.

Therefore, conventionally, as shown in FIGS. 23 and 24, in the reading device, the reflected light emitted from the light source unit 41 and reflected by the original 35a and the reflection mirrors 43a to 43d passes through the lens 44 to the CCD 1. When an image is formed on the surface, if the central portion of the surface of the CCD 1 has a larger amount of light than the end portions, the optical path of the portion corresponding to the central portion of the CCD surface in the optical path of the reflected light. A shading plate (light amount adjusting plate) 90 that blocks the light is attached in the immediate vicinity of the lens 44 via a mounting screw 91 to make the light amount on the CCD surface uniform from the central portion to the end portion.

[0004]

However, a special shading plate is required to equalize the amount of light on the CCD surface from the central portion to the end portion, which causes a cost increase.

Further, the outer shape of the shading plate for equalizing the light amount from the central portion to the end portion on the CCD surface is very difficult to form in consideration of variations in each reading device. If the amount of light to the CCD is insufficient, the reliability of the image data is reduced and the obtained copied image becomes unclear.

The present invention was devised in view of such circumstances, and as described above, the amount of light on the CCD image forming surface can be made substantially uniform from the central portion to the end portion, and the reliability of the image is improved. In addition, it is an object of the present invention to provide a reading device of an image forming apparatus that can obtain a clear image.

[0007]

[Means for Solving the Problems]

(1) A reading device of an image forming apparatus according to a first aspect of the present invention is a reading device that integrally includes a light source unit, a mirror, a lens, and a CCD, and forms light from the light source unit on the CCD. It is characterized in that the lens is movably arranged in the optical path so that the amount of blocking the optical path can be varied so that the light quantity becomes uniform from the central portion to the end portion on the CCD image forming surface.

(2) According to a second aspect of the present invention, there is provided a reading device for an image forming apparatus according to the first aspect, wherein the lens itself obstructs the optical path from the central portion to the end portion. The projection is integrally formed on the outer shape of the main body of the lens.

(3) A reading device of an image forming apparatus according to a third aspect of the present invention is the reading device according to the first aspect, wherein the ring member is rotatably attached to the lens body, and the ring member itself. Is characterized in that a convex portion is integrally formed on the outer peripheral portion of the annular member so that the ratio of blocking the optical path gradually decreases from the central portion to the end portion.

[0010]

[Action]

(1) In the reading device according to the first aspect, when the light from the light source unit forms an image on the CCD and the light amount at the central portion is larger than at the end portion on the CCD image forming surface, the lens is moved, The amount of light is adjusted by blocking the portion corresponding to the central portion of the CCD image forming surface in the optical path by the lens itself so that the amount of light on the CCD image forming surface is uniform from the central portion to the end portion. As a result, the reliability of the image is improved and a clear image can be obtained.

(2) In the reading device of the second aspect, since the convex portion is integrally formed on the outer shape of the main body of the lens, the movement amount of the lens along the optical axis direction when correcting the light amount is reduced. Therefore, the reading device can be downsized. After the lens is moved in the optical axis direction, the lens is moved in the circumferential direction, so that the amount of light can be finely adjusted. As a result, the light amount distribution on the CCD image plane becomes more uniform,
Further, the reliability of the image is improved, and a clearer image can be obtained.

(3) In the reading device of the third aspect, since the annular member having the convex portion is provided separately from the lens body, the annular member is moved in the circumferential direction with the lens body fixed. Since the light amount can be finely adjusted by using the light, the operability is improved.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a reading device according to the present invention will be described below in detail with reference to the drawings. Here, a digital copying machine will be described as an example of a copying machine equipped with a reading device.

FIG. 2 is a sectional view showing the overall construction of the digital copying machine.

As shown in FIG. 2, the copying machine 30 is provided with a scanner unit 31, a laser printer unit 32, a multi-stage paper feeding unit 33 and a sorter 34.

The scanner unit 31 includes a document placing table 35 made of transparent glass and a double-sided automatic document feeder (RDF) 3.
6 and a reading device (scanner unit) 40.

The multi-stage paper feeding unit 33 includes the first cassette 5
It has the 1st, 2nd cassette 52, the 3rd cassette 53, and the 4th cassette 54 which can be added by selection. In the multi-stage paper feeding unit 33, the papers are fed one by one out of the papers stored in the cassettes of the respective tiers and are conveyed toward the laser printer unit 32.

The double-sided automatic document feeder 36 sets a plurality of documents at one time and automatically feeds the documents one by one to the reading device 40, so that one side of the document is selected according to the operator's selection. Alternatively, the reading device 40 is configured to read both sides.

The reader 40, as shown in FIG.
A light source unit (lamp reflector assembly) 41 for exposing a document, a plurality of reflection mirrors 43 for guiding a reflected light image from the document 35a to a reading unit 42 including a photoelectric conversion element (CCD) 1, and a reflected light image from the document 35a. It includes a lens 44 for forming an image on the CCD 1 of the reading unit 42.

When scanning a document placed on the document table 35, the scanner section 31 is configured to read the document image while moving the reading device 40 along the lower surface of the document table 35. When the automatic document feeder 36 is used, the document image is read while the document is conveyed while the reading device 40 is stopped at a predetermined position below the automatic document feeder 36. .

The image data obtained by reading the original image with the reading device 40 is sent to an image processing unit (not shown), which will be described later, and after being subjected to various processes, is temporarily stored in the memory of the image processing unit. In response to the output instruction, the image data in the memory is given to the laser printer unit 32 to form an image on the paper.

The laser printer unit 32 includes a manual document tray 45, a laser writing unit 46, and an electrophotographic process unit 47 for forming an image.

The laser writing unit 46 is a semiconductor laser which emits a laser beam corresponding to image data from the above-mentioned memory, a polygon mirror which deflects the laser beam at an equal angular velocity,
The laser beam deflected at a constant angular velocity is used for the electrophotographic process unit 47.
It has an f-θ lens and the like for correcting so that the light is deflected at a constant speed on the photosensitive drum 48.

The electrophotographic process section 47 has a charging device, a developing device, a transfer device, a peeling device, a cleaning device, a static eliminator and a fixing device 49 around the photosensitive drum 48 according to a known manner.
Is arranged.

A conveying path 50 is provided on the downstream side of the fixing device 49 in the conveying direction of the sheet on which the image is to be formed. The conveying path 50 is connected to the conveying path 57 leading to the sorter 34 and the multi-stage sheet feeding unit 33. It branches into a communication path 58 which is in communication.

The conveying path 58 is branched in the multi-stage sheet feeding unit 33, and the reversing conveying path 5 is formed as a conveying path after branching.
0a and a double-sided / composite transport path 50b are provided.

The reversing conveyance path 50a is a conveyance path for reversing the front and back sides of a sheet in a double-sided copy mode for copying both sides of a document. The double-sided / composite conveying path 50b is used for the photosensitive drum 48 from the reverse conveying path 50a in the double-sided copying mode.
Image on the photosensitive drum 48 without reversing the paper in the single-sided composite copy mode in which the paper is conveyed to the image forming position or the composite copy is performed in which the image of the different original or the image of the toner of different color is formed on one surface of the paper. It is a transport path for transporting to the formation position.

The multi-stage sheet feeding unit 33 includes a common conveyance path 56, and the common conveyance path 56 includes the first cassette 51 and the second cassette 51.
The sheets from the cassette 52 and the third cassette 53 are carried out toward the electrophotographic process section 47.

The common conveyance path 56 is used for the electrophotographic process section 4
On the way to 7, the recording medium merges with the conveyance path 59 from the fourth cassette 54 and communicates with the conveyance path 60.

The conveying path 60 merges at the confluence point 62 with the double-sided / composite conveying path 50b and the conveying path 61 from the manual feed tray 45, and joins between the photosensitive drum 48 of the electrophotographic process section 47 and the transfer device. It is configured to communicate with the image forming position, and the confluence point 62 of these three conveying paths is provided at a position close to the image forming position.

Therefore, the laser writing unit 46
Also, in the electrophotographic process section 47, the image data read from the above-mentioned memory is formed as an electrostatic latent image on the surface of the photosensitive drum 48 by scanning the laser beam by the laser writing unit 46, and is formed by the toner. The toner image visualized is a multi-stage paper feeding unit 3
3 is electrostatically transferred and fixed on the surface of the sheet conveyed from 3. The sheet on which the image is formed in this way is fixed in the fixing unit 49.
Is sent to the sorter 34 via the transport path 50 and the transport path 57, or is transported to the reverse transport path 50a via the transport path 50 and the transport path 58.

Next, the structure and function of the image processing unit included in the copying machine 30 will be described.

FIG. 4 is a block diagram of an image processing unit included in the copying machine 30 shown in FIG.

The image processing unit included in the copying machine 30 is
An image data input unit 70, an image processing unit 71, an image data output unit 72, a memory 73 including a RAM (random access memory), and a central processing unit (CPU) 74.
It has.

The image data input section 70 is a CCD section 70.
a, histogram processing unit 70b and error diffusion processing unit 7
0c is included.

The image data input unit 70 binarizes and converts the image data of the original read from the CCD of the reading unit 42 of FIG. 2 to obtain a histogram as a binary digital amount, and an image by the error diffusion method. It is configured to process the data and temporarily store it in the memory 73.

That is, in the CCD section 70a, after the analog electric signal corresponding to each pixel density of the image data is A / D converted, MTF correction, black-and-white correction or gamma correction is performed, and 256 gradations (8 bits). Is output to the histogram processing section 70b.

In the histogram processing section 70b, the digital signal output from the CCD section 70a is added for each pixel density of 256 gradations to obtain density information (histogram data), and if necessary, the obtained histogram data is It is sent to the CPU 74 and also as pixel data to the error diffusion processing unit 70c.

The error diffusion processing unit 70c uses the error diffusion method, which is a kind of pseudo halftone processing, that is, the method of reflecting the binarization error in the binarization judgment of the adjacent pixels.
The 8-bit / pixel digital signal output from the unit 70a is converted into 1-bit (binary), and a redistribution operation is performed to faithfully reproduce the local area density in the original.

The image processing section 71 includes a multi-valued processing section 71a,
71b, a combination processing unit 71c, a density conversion processing unit 71d, a scaling processing unit 71e, an image processing unit 71f, an error diffusion processing unit 71g, and a compression processing unit 71h.

The image processing section 71 is a processing section for finally converting the input image data into image data desired by the operator, and until it is stored in the memory 73 as finally converted output image data. The processing unit is configured to process. However, each of the above-described processing units included in the image processing unit 71 functions as necessary and may not function.

That is, in the multi-value quantization processing units 71a and 71b, the data binarized by the error diffusion processing unit 70c is converted into 256 gradations again.

In the synthesizing unit 71c, a logical operation for each pixel, that is, a logical sum, a logical product, or an exclusive logical sum is selectively performed. The data that is the target of this calculation is the pixel data stored in the memory 73 and the bit data from the pattern generator (PG).

In the density conversion processing unit 71d, the relationship between the input density and the output density is arbitrarily set for the 256 gradation data signal based on a predetermined gradation conversion table.

In the scaling processing section 71e, pixel data (density value) for the scaled target pixel is obtained by performing interpolation processing with the known data that is input according to the instructed scaling ratio. After the scanning is scaled, the main scanning is scaled.

In the image processing section 71f, various image processings may be performed on the input pixel data, and information collection such as feature extraction may be performed on the data string.

The error diffusion processing section 71g performs the same processing as the error diffusion processing section 70c of the image data input section 70.

In the compression processing unit 71h, binary data is compressed by the encoding called run length. Regarding the compression of image data, the compression in the final processing loop functions when the final output image data is completed.

The image data output unit 72 includes a restoration unit 72a,
The multilevel halftoning processing unit 72b, the error diffusion processing unit 72c, and the laser output unit 72d are included.

The image data output unit 72 restores the image data stored in the memory 73 in a compressed state to the original 2
It is configured to convert again to 56 gradations, perform error diffusion of four-valued data that is a smoother halftone expression than binary data, and transfer the data to the laser output unit 72d.

That is, the decompression unit 72a decompresses the image data compressed by the compression processing unit 71h of the image processing unit 71.

In the multi-value quantization processing section 72b, the image processing section 71
Processing similar to that of the multi-value quantization processing units 71a and 71b is performed. In the error diffusion processing unit 72c, the image data input unit 70
Processing similar to that of the error diffusion processing unit 70c is performed.

In the laser output section 72d, the digital pixel data is converted into a laser on / off signal based on a control signal from a sequence controller (not shown), and the laser is turned on / off.

The data handled in the image data input section 70 and the image data output section 72 is the memory 73.
In order to reduce the capacity of the data, it is basically stored in the memory 73 in the form of binary data, but it can be processed in the form of four-valued data in consideration of the deterioration of the image data.

Next, as shown in FIG. 3, the driving of the scanner section 31 will be described in more detail. In the scanner unit 31, in order to reciprocate the reading device 40 in the scanning direction, a guide shaft 31e for guiding the reading device 40 in the scanning direction (S in the drawing) is provided near a side portion of the reading device 40 in the moving direction. , Reading device 4
An endless drive wire 31a for moving 0 is wound around a drive pulley 31b and an idle pulley 31c, and a motor 31d for driving the drive pulley 31b is provided.

On the other hand, when the automatic document feeder 36 is used, after the reading device 40 is moved to a predetermined position below the automatic document feeder 36 by the motor 31d or the like,
As is well known, with the reading device 40 stopped, the original image is read by the reading device 40 while the original 35a on the original placing table 35 is being conveyed in the automatic original feeding device 36.

Next, the reading unit 42 in the reading device 40 will be described. Reading unit 42
Then, C which is a photoelectric conversion element on the optical path from the lens 44
The CD 1 is attached, and further, as shown in FIGS. 5, 6 and 7, an adjusting mechanism section 2 for attaching the CCD 1 so as to be optically adjustable is provided.

Such an adjusting mechanism section 2 is provided on the outer surface of the reading device 40 to which the lens 44 is attached or the opening through which the light from the lens 44 passes is provided. Z direction as the optical axis direction of, the rotation direction for rotating about the optical axis,
It can be adjusted in the Y direction as the vertical direction, the X direction as the horizontal direction, and the tilt direction with respect to the optical axis.

First, in order to mount the adjusting mechanism section 2 described above, a frame body 3 made of a plate-like body is provided on the outer surface of the reading device 40 so as to surround the optical path in four directions, that is, in the Y direction and the X direction. A Z-direction adjusting portion 4 that is movable in the Z direction, which is the optical axis direction of the optical path, is slidably fitted to the three surfaces of the frame body 3.

The Z-direction adjusting portion 4 as described above is formed into a substantially box-like shape so that the Z-direction adjusting portion 4 can be fitted to the three surfaces of the frame body 3 and the rotation direction adjusting portion 5 to be described later can be fitted therein. It has an opening through which an optical path is passed, and further has an upright portion 4a having a rectangular cross section as a guide for moving the Z-direction adjusting portion 4 in the optical axis direction on the lower surface, so that the Z-direction adjusting portion 4 can be stabilized. It has a leaf spring 4b as a biasing means for moving it.

Therefore, an opening 3b is provided in the lower portion 3a of the frame 3 so that the upright portion 4a is fitted, and a fixing screw 4c for fixing the leaf spring 4b is provided in the frame 3.
Is attached to the upper part 3c from above.

Further, in the Z-direction adjusting section 4, the standing section 4a
A Z-direction adjusting screw 4e can be screwed to the female screw portion of the reading device 40 by penetrating the upright portion 4a and the coil spring 4d through the adjusting coil spring 4d between the reading device 40 and the reading device 40. The adjusting screw 4e for Z direction described above.
The Z-direction adjuster 4 can be moved in the Z-direction by adjusting. Further, a Z direction fixing screw 4f for fixing the adjusted Z direction adjusting portion 4 is provided on the frame upper portion 3
It is attached through c.

Next, description will be given of the above-mentioned rotation direction adjusting section 5 mounted so as to be rotatable around the above-mentioned optical axis. The rotation direction adjusting unit 5 is provided with a recess into which a Y direction adjusting unit 6 to be described later is fitted, and is formed into a substantially box shape having an opening through which the above optical path passes.

Further, the rotation direction adjusting section 5 centers the optical axis at two locations on the outer surfaces which are substantially opposite to each other with the optical axis sandwiched therebetween so that the optical axis can be stably rotated about the optical axis. And has arcuate outer surfaces 5a, 5a. Therefore, also on the inner surface of the Z-direction adjusting portion 4, arc-shaped inner surfaces 4g, 4g which are in sliding contact with the arc-shaped outer surfaces 5a, 5a are formed.

In addition, the rotating direction adjusting portion 5 is provided with a rotating leaf spring 5b for urging the rotating direction adjusting portion 5 in one direction and a concave surface 4h adjacent to one arcuate inner surface 4g of the Z direction adjusting portion 4 and rotating. While being sandwiched between the outer surface of the direction adjusting portion 5 and the outer surface of the portion of the Z direction adjusting portion 4 facing the concave surface 4h, the rotation direction adjusting screw 5c can be moved by a screw through the above portion. Is attached to.

As a result, the tip of the rotating direction adjusting screw 5c abuts on the rotating direction adjusting portion 5, and the rotating leaf spring 5b is rotated.
By moving up and down against the urging force of, the rotation direction adjusting unit 5 is rotatable about the optical axis.

Next, the above-mentioned Y-direction adjusting portion 6 mounted so as to be movable in the Y direction as the vertical direction with respect to the optical axis will be described. The Y-direction adjusting portion 6 is in sliding contact with both Y-direction end surfaces of an X-direction adjusting portion 7 described later, and
The direction adjusting portion 7 is formed in a substantially box shape having a concave portion that allows the direction adjusting portion 7 to slide in the X direction, and an opening through which the optical path passes is formed in the central portion thereof.

Further, in the Y-direction adjusting portion 6, a pair of substantially F-shaped adjusting leaf springs 6a for urging the Y-direction adjusting portion 6 upward are provided to adjust the rotation direction with the lower outer surface of the Y-direction adjusting portion 6. It is sandwiched between the lower inner surface of the portion 5 and the optical axis so as to be equidistant from the optical axis, and on the other hand, it comes into contact with the upper and outer surfaces of the Y-direction adjusting portion 6 so as to urge the adjusting leaf springs 6a. A Y-direction adjusting screw 6b capable of moving the Y-direction adjusting unit 6 against the above is attached through a screw at the center of the upper surface of the rotation-direction adjusting unit 5.

Thus, when the Y-direction adjusting screw 6b is rotated, the Y-direction adjusting screw 6b moves up and down, and the Y-direction adjusting portion 6 is stably moved up and down, that is, Y by the biasing force of each adjusting leaf spring 6a. You can move in any direction. Therefore, a Y-direction adjusting notch 6c is formed in the upper center of the Z-direction adjusting portion 4 so that the Y-direction adjusting screw 6b can be rotated from above by a driver or the like.

Next, the above-mentioned X-direction adjusting portion 7 mounted so as to be movable in the X-direction as the left-right direction with respect to the optical axis will be described. The X-direction adjusting unit 7 is formed in a substantially box shape having a recess having an inner surface that slides on both end faces of the tilt adjusting unit 8 in the Y direction, and further has an opening through which the optical path passes in the center thereof. There is.

Further, a pair of fixing screws 8a, which are respectively inserted from the outside in order to rotate the tilt direction adjusting part 8 or to fix the tilt direction adjusting part 8, are axially supported on the X direction adjusting part 7. A pair of projecting pieces 7a are formed at one end of the X-direction adjusting portion 7 in the X direction so as to face each other outward in the Z direction.

In order to move the X-direction adjusting portion 7 in the X-direction, an inclined portion 7b is formed at one end of the X-direction adjusting portion 7 in the X-direction. That is, the inclined portion 7
As for b, the X-direction length in the X-direction adjusting unit 7 is gradually shortened from the bottom to the top.

Moreover, in the X-direction adjusting portion 7, the X-direction adjusting leaf spring 7c is sandwiched between the X-direction adjusting portion 7 and the Y-direction adjusting portion 6 on the opposite side of the inclined portion 7b, while the X-direction adjusting leaf spring 7c is inserted. The direction adjusting screw 7d is inserted downward from the upper surface of the Y direction adjusting portion 6 in the Y direction so that the tip of the direction adjusting screw 7d comes into contact with the inclined portion 7b. By rotating the X direction adjusting screw 7d to move it up and down, The X-direction adjusting portion 7 can be moved against the biasing force of the X-direction adjusting leaf spring 7c. On the other hand, an X-direction adjusting cutout portion 7e is formed at one end of the upper surface of the Z-direction adjusting portion 4 so that the X-direction adjusting screw 7d can be rotated by inserting a driver or the like from above.

Next, the above-mentioned tilt direction adjusting portion 8 mounted so as to be rotatable in the tilt direction with respect to the optical axis will be described. The tilt direction adjusting portion 8 is provided with an opening and a hollow portion through which the optical path is passed, and further, a pair of plate-shaped pieces 8d to which the fixing screws 8a are respectively screwed are attached to the protruding pieces 7a. It has to be inside.

Further, the tilt direction adjusting portion 8 has a substantially square-shaped tilt direction adjusting leaf spring between the tilt direction adjusting portion 8 and the X direction adjusting portion 7 on the opposite side of the plate-shaped pieces 8d. 8b
Since the tilt adjusting screw 8c is inserted into the female screw portion of the X adjusting member 7 through the tilt adjusting member 8 and the tilt adjusting leaf spring 8b, the tilt adjusting screw 8c By rotating and moving in the Z direction, the tilt direction adjusting portion 8 can be rotated in the tilt direction.

Further, the adjusting mechanism section 2 is provided with an adjusting mechanism section cover 9 having a substantially rectangular plate shape for restricting the movement of the adjusting sections 5, 6, 7 in the Z direction. Are attached to the four corners of the Z-direction adjuster 4. Therefore, such an adjusting mechanism cover 9 is provided with an opening through which the optical path is passed, and is further provided with a notch so that each of the projecting pieces 7a can be projected outward.

Then, the CCD mounting plate 10 for fixing the CCD 1 to the adjusting mechanism section 2 is attached to the tilt direction adjusting section 8 by a pair of fixing screws 10a, and the output from the CCD 1 is taken out. In this case, the CCD board 11 serving as a board for each terminal is four mounting screws 11a.
Is attached to the CCD mounting plate 10.

The CCD mounting plate 10 is formed with an opening through which the optical path passes, while the CCD board 11 is provided with a pair of fixing screws 10a so that the fixing screws 10a can be detached from the outside. An opening is formed.

In this way, the adjusting mechanism section 2 is connected to the CCD 1
Can be adjusted in the Z direction as the optical axis direction of the optical path, the rotation direction in which the optical axis is rotated about the optical axis, the Y direction as the vertical direction, the X direction as the horizontal direction, and the tilt direction with respect to the optical axis. ing.

Next, the magnification adjusting section 12 for adjusting the magnification by changing the optical path length of each reflection mirror 43 ... The magnification adjusting unit 12 is mounted above and includes a Z-direction reflecting mirror 43c.

As shown in FIG. 8, such a magnification adjusting section 12 has a mounting plate 12a that covers the back side of the reflecting mirror 43c having a substantially rectangular plate shape, and both ends of the reflecting mirror 43c in the longitudinal direction elastically. The holding plate 12b has a pair of U-shaped holding plates 12b for holding, and each holding plate 12b is fixed to both ends of the mounting plate 12a in the longitudinal direction, while the mounting plate 12a holds the reflection mirror 43c. As an attachment for attaching at a predetermined angle, it has an angle portion 12f bent at a predetermined angle.

The magnification adjusting section 12 also includes a reflection mirror 4
3 adjustment screws 1 for fine adjustment of the mounting position of 3c
2c, 12d, 12d are provided at both ends in the longitudinal direction of the mounting plate 12a, and one adjusting screw 12c is provided at one end of the mounting plate 12a toward the reflection mirror 43c toward the center line in the longitudinal direction. While the other two adjustment screws 12d are attached to the female screw portion of the attachment plate 12a so as to come into contact with the back surface of 43c, the other two adjustment screws 12d face a position different from the above center line and are equidistant from the above center line. Is attached to the female screw portion of the attachment plate 12a so as to come into contact with the back surface of the reflection mirror 43c.

As a result, the above three adjusting screws 12 are provided.
By moving c, 12d, and 12d in the same direction, it becomes possible to change the optical path length, while adjusting screw 12c
By moving the two adjusting screws 12d in the opposite directions, the optical path can be changed in the left and right directions. Further, by moving the two adjusting screws 12d in opposite directions, the optical path can be changed in the vertical direction. By adjusting the adjustment screws 12c, 12d, 12d in this manner, the optical path reflected by the reflection mirror 43c is adjusted to
It can be adjusted by changing it in the vertical direction. In this way, the adjusting mechanism section 2 and the magnification adjusting section 12 constitute an optical adjusting mechanism.

Next, an optical adjusting method of the CCD 1 in the reading device 40 using the adjusting mechanism section 2 and the magnification adjusting section 12 will be described. First, as shown in FIG. 9 using the motor 31d shown in FIG. 3, on the side where the reading reversal operation is performed, outside the area for placing the original, and the light from the light source unit 41 is condensed and the original is read. It is moved to a position where the reflected light from the mounting table 35 can be received.

Subsequently, the oscilloscope 13 for measurement is connected to the CCD substrate 11 having the terminals for measurement from the CCD 1 and the adjustment pattern 14 shown in FIG. Place it on the table 35,
The light source unit 41 is turned on, and the adjustment pattern 14
Is read into the CCD 1 and each adjusting screw is adjusted by the driver 15 according to the following procedure to adjust the adjusting mechanism section 2 and the magnification adjusting section 12, as shown in FIG. The adjustment procedure is: Focusing → Optical axis alignment → Light intensity adjustment →
The order is focusing → optical axis alignment → position alignment → magnification alignment.

As shown in FIG. 11, the adjusting pattern 14 is formed in a rectangular shape, and straight lines in the lateral direction are provided on the rectangular pattern at predetermined intervals. In the adjustment pattern 14, (1), (7) and (13) are read width (position) adjustment patterns, and (3), (5), (9) and (11) are focus adjustment patterns. (3 / mm), (2), (4), (6), (8), (10),
(12) is an optical axis alignment pattern.

First, for focusing, the Z-direction adjusting unit 4 in the adjusting mechanism unit 2 is moved by moving the Z-direction adjusting screw 4e while observing the oscilloscope 13, and as shown in FIG. As shown in FIG. 13B after the focus adjustment, the Z direction adjustment is performed from 13 (a) to the position where the waveforms corresponding to (3), (5), (9), and (11) in the adjustment pattern 14 appear. Adjust Part 4. In addition, after adjusting so that the waveforms of the (3), (5), (9), and (11) parts are maximized and have a uniform width on the left and right, the fixing screw 4f for the Z direction is set. Tighten and fix the Z-direction adjusting unit 4. As shown in FIG. 13C, if the waveforms (3), (5), (9), and (11) appear, the waveforms at other locations may be ignored.

Next, in the optical axis alignment, the rotation direction adjusting unit 5, the Y direction adjusting unit 6, and the tilt direction adjusting unit 8 are respectively moved to pass through FIG. 14 (a) to FIG. 14 (b).
As shown in (c), the widths of the waveforms indicating (4) and (10) are flat, and adjustment is performed so that the (2) and (12) portions are exposed. After such adjustment, the Y-direction adjusting unit 6 is moved up and down slightly so that the waveform with respect to the central axis moves symmetrically.

Regarding claim 1, next, in the light quantity adjustment,
As shown in FIGS. 9 and 10, the openings 31e and 31f at the bottom of the frame of the scanner unit 31 and the reading device 4 are provided.
Lens mounting part 40 to which the lens 44 of 0 is mounted
When the lens 44 is moved from the opening 40b (see FIG. 10) in the lower part of a to the direction a along the mounting portion 40a by a finger, the amount of light received by the CCD 1 on the oscilloscope 13 is shown in FIG. Adjust so that the light intensity is as flat as possible. A portion of the outer shape of the lens 44 corresponding to the central portion of the CCD surface in the reflected light is blocked and the amount of light is adjusted. The outer shape of the lens 44 is similar to that of a general lens. The solid line is before the light amount adjustment, and the broken line is after the light amount adjustment.

Actually, if the light quantity received by the CCD 1 is lower than a certain level, the gradation of the image is deteriorated and the reliability of the image is deteriorated. Therefore, the light quantity received by the CCD 1 is the highest on the line of the CCD 1. And the minimum difference in light intensity is 2
Adjust so that it is within 5%.

Next, since the lens 44 is once moved, focusing is performed by the same procedure as described above, and then optical axis alignment is performed. Then, the focus and the optical axis alignment are repeated until the optimum position is reached. After completing all the adjustments, the lens 44 is fixed by the lens fixing screw 44b.

As described above, the amount of light on the CCD image forming surface becomes substantially uniform from the center to the end, the reliability of the image is improved, and a clear copy image can be obtained.

According to claim 2, the outer shape of the main body of the lens 44 has a shape as shown in FIG.
18 and FIG.
9 shows. The outer shape of the main body of the lens 44 mounted in the reading device 40 is arranged so that the light quantity at the central portion of the image forming surface of the CCD 1 is most blocked with respect to the optical axis forming the image on the image forming surface of the CCD 1 in the reading device 40. , The convex portion 44a is arranged integrally with the lens 44.

Lens 4 integrally having this convex portion 44a
The outer shape of the main body of No. 4 has a shape such that the amount of light decreases toward the end of the image plane of the CCD 1. Here, the shape of the convex portion 44a will be described.

The shape of the convex portion 44a of the outer shape of the main body of the lens 44 is such that when the light source unit 41 of the reading device 40 irradiates a document on the document table 35 with a flat light amount distribution in the main scanning direction. As for the irradiation light, the light quantity distribution on the image forming surface of the CCD 1 has a lower light quantity at the end portion with respect to the central portion according to the cos ⁴ θ law of the lens 44, and therefore it is necessary to make the shape in accordance with the light quantity distribution. The shape of the ridgeline portion of the convex portion 44a is determined by the function shown in FIG. Where x
Has a domain of −1 ≦ x ≦ 1. θ is the maximum angle of view in the lens 44. 2θ / a | x in cos ⁴ ()
|

However, finally, it is necessary to finely adjust the shape of the convex portion 44a in accordance with the distribution of the light amount of the lens 44, the light source unit 41, the reflectance of the reflection mirror 43, etc. for each copying machine.

In addition, the light source unit 41 itself includes the lens 44.
In order to compensate for the change in the light amount distribution due to the cos ⁴ θ rule of, the method in which the light amount distribution for irradiating the document on the document table 35 in the main scanning direction raises the light amount in the central part with respect to the end part is often used. ing. In such a case, the light amount distribution on the image plane of the CCD 1 also does not conform to the cos ⁴ θ rule of the lens 44, and therefore the shape of the convex portion 44 a of the outer shape of the main body of the lens 44 is also different for each copying machine. Each time we make a prototype, we will confirm the shape and decide.

In the case of claim 2, the method of adjusting the amount of light by the lens 44 is the same as that of claim 1, but the outer shape of the main body of the lens 44 has a convex portion 4 as compared with the method of claim 1.
Since it has 4a, the movement amount of the lens 44 for adjustment in the direction (optical axis direction) of FIG. 19 (light amount correction in the first step) is small, and the reading device 40 can be downsized. Further, similarly, since it has the convex portion 44a, after the light amount correction in the first stage, as shown in FIG. 19, the lens 44 is moved in the direction B (circumferential direction) so that the light amount correction can be performed finely. Adjustment (light amount correction in the second step) becomes possible, the reliability of the image can be improved, and a clearer copy image can be obtained.

Regarding the third aspect, in the lens 44 described in the second aspect, as shown in FIG. 20, the shape of the convex portion of the outer shape of the main body for correcting the light quantity is different from the main body of the lens 44 (second part). A light amount correction component) is provided, and an annular member 44c, which is a separate component, is attached to the main body of the lens 44 so as to be movable in the circumferential direction. The ring member 44c
The convex portion 44a is integrally formed on itself.

21 and 22 show the construction of the lens 44 in the reading device 40 in the third aspect. As the method of adjusting the amount of light by the lens 44, similarly to the method described in claims 1 and 2, adjustment in the direction (optical axis direction) in FIG. 22 (correction of the amount of light in the first step) is performed. At this time, the main body of the lens 44 is fixed by the lens fixing screw 44b shown in FIG.

Thereafter, the annular member 44c as the second light amount correction component outside the main body of the lens 44 is moved in the direction B (circumferential direction) to finely adjust the light amount correction (second
Light level correction). After adjusting the light amount, the ring member 44c is fixed to the main body of the lens 44 by screw locking or the like.

According to the method described in claim 3, in the light amount correction in the first step, the amount of movement of the lens 44 in the optical axis direction (direction a in FIG. 22) is the same as described in claim 2. Since the number is small, the reader 40 can be downsized.

Further, as the second stage light amount correction, the annular member 44c is formed as a separate component from the lens 44 main body, so that the lens 44 main body is fixed after the first stage light amount correction is completed, In that state, it is possible to perform the second stage light amount correction, that is, to move only the annular member 44c in the direction (circumferential direction). That is, since the body of the lens 44 does not need to be moved in the circumferential direction, there is an advantage that the body of the lens 44 does not deviate at that time, and the light amount can be reliably corrected. Can raise
A clearer copy image can be obtained.

Here, general items for attaching the lens to the reading device will be described. Usually, the lens is provided with markings indicating the mounting position in the circumferential direction. Since the lens of the copying machine is made by combining a plurality of lenses, the optimum resolution for mounting on the reading device can be obtained as a lens after assembly despite variations in the resolution and distortion of the plurality of lenses. To do so. It is difficult to manufacture an isotropic lens that does not need to be marked and the mounting position need not be specified, and it causes a significant cost increase.

As described above, the main body of the lens 44 is fixed at a predetermined position in the circumferential direction, and then the annular member 44.
If only c is moved in the circumferential direction, it is not necessary to use a special lens itself.

Next, in the alignment, the X-direction adjusting unit 7 is moved by the X-direction adjusting screw 7d, and the C portion of the alignment signals A, B and C shown in FIG. )
The waveform outputs (1) shown in are combined (when the C part is enlarged as shown in FIG. 15C, it is performed in the delay mode of the oscilloscope 13). At this time, (2), (4), (1
Adjust the X-direction adjusting unit 7 while confirming that 0) and (12) are flat.

After the adjustment as described above, the focus adjustment, the optical axis adjustment, and the position adjustment are performed again by checking again whether they are as shown in FIG. 12, for example.

Next, in the magnification matching, the adjustment pattern 1
When the C section and (1) are aligned as described above so that the interval of (1) and (13) of 4 and the reading width match,
3 adjustment screws 12c in the magnification adjusting unit 12 so that the difference between the section A and (13) in FIG.
12d and 12d are moved in substantially the same direction with respect to the optical axis to change the optical path length to adjust the magnification.

By providing the adjusting mechanism section 2 and the magnification adjusting section 12 in this manner, it is possible to prevent the trouble of attaching and detaching a dedicated adjusting jig and the adverse effect on the attachment accuracy of the CCD 1 as in the conventional case. The labor and skill of attaching and detaching the above jig can be saved, and the optical adjustment of the CCD 1 can be easily performed.

[0110]

【The invention's effect】

(1) According to the reading device of the first aspect, by moving the lens, the lens itself blocks the portion corresponding to the central portion of the CCD image forming surface in the optical path to adjust the light amount, and the CCD image forming is performed. Since the amount of light on the surface can be made uniform from the central portion to the end portions, the reliability of the image is improved and a clear image can be obtained.

(2) According to the reading device of the second aspect, since the convex portion is integrally formed on the outer shape of the main body of the lens, the movement amount of the lens along the optical axis direction when correcting the light amount can be reduced. It is possible to reduce the number, and the reader can be downsized, and the light amount can be finely adjusted by moving the lens in the circumferential direction, and the light amount distribution on the CCD image forming surface can be made more uniform, and the image reliability can be further improved. As a result, a clearer image can be obtained.

(3) According to the reading device of the third aspect, since the annular member having the convex portion is separated from the lens body, the annular member is moved in the circumferential direction while the lens body is fixed. The amount of light can be finely adjusted to improve the operability.

[Brief description of drawings]

FIG. 1 is a perspective view of a reading device in a digital copying machine according to a first embodiment of the present invention.

FIG. 2 is a configuration diagram of a digital copying machine according to an embodiment of the present invention.

FIG. 3 is a configuration diagram of a scanner unit of the digital copying machine of the embodiment.

FIG. 4 is a block diagram of a copy control unit of the digital copying machine of the embodiment.

FIG. 5 is an exploded perspective view of an adjusting mechanism unit in the reading device according to the embodiment.

FIG. 6 is a side view of an adjusting mechanism section and a magnification adjusting section in the reading apparatus according to the embodiment.

FIG. 7 is a cross-sectional view of the adjusting mechanism section.

FIG. 8 is a perspective view of the magnification adjusting unit.

FIG. 9 is an explanatory diagram of an adjusting method of the adjusting mechanism section and the magnification adjusting section.

FIG. 10 is a perspective view showing a structure of a mounting portion of a lens.

FIG. 11 is a plan view of an adjustment pattern in the above adjusting method.

FIG. 12 is an example of an adjustment pattern detected by the above adjustment method.

FIG. 13 is another example of the adjustment pattern detected by the above adjustment method.

FIG. 14 is still another example of the adjustment pattern detected by the above adjustment method.

FIG. 15 is still another example of the adjustment pattern detected by the above adjustment method.

FIG. 16 is an explanatory diagram of light amount correction in the first embodiment.

FIG. 17 is an explanatory diagram of a shape of a lens according to a second example.

FIG. 18 is a perspective view of a reading device according to a second embodiment.

FIG. 19 is a side view of an adjusting mechanism section and a magnification adjusting section in the reading apparatus according to the second embodiment.

FIG. 20 is an explanatory diagram of a lens shape according to the third example.

FIG. 21 is a perspective view of a reading device according to a third embodiment.

FIG. 22 is a side view of an adjusting mechanism section and a magnification adjusting section in the reading apparatus according to the third embodiment.

FIG. 23 is a perspective view of a reading device according to a conventional example.

FIG. 24 is a side view of a conventional reading device.

[Explanation of symbols]

 1 ... CCD 2 ... Adjustment mechanism part 40 ... reading device 40a ... lens mounting part 40b ... aperture part 41 ... light source unit 43a to 43d ... reflection mirror 44 ... lens 44a ... convex part 44b ... Lens fixing screw 44c ... Toroidal member

Claims (3)

[Claims] 1. A light source unit, a mirror, a lens, and a CCD
In a reading device that integrally includes a light source unit and forms an image of light from a light source unit on a CCD, a lens itself changes an amount of blocking an optical path so that a light amount is uniformed from a central portion to an end portion on a CCD image forming surface. A reading device of an image forming apparatus, wherein a lens is movably arranged in the optical path. 2. The convex portion is integrally formed on the outer shape of the main body of the lens so that the ratio of the light blocking by the lens itself gradually decreases from the central portion to the end portion. A reading device of the image forming apparatus. 3. A ring member is rotatably attached to the body of the lens, and a convex portion is formed on the outer shape of the ring member so that the ratio of the light blocking by the ring member itself gradually decreases from the central portion to the end portion. The reading device of the image forming apparatus according to claim 1, wherein the unit is integrally formed.